Graphene-Anchored p-Type CuBO2 Nanocrystals for a Transparent Cold Cathode

Hierarchically crystalline copper borate nanosheets as a freestanding electrode for a hybrid supercapacitor

In this study, we have suggested a straightforward approach to fabricating a binder-free electrode of hierarchically crystalline copper borate (Cu-Bi) nanosheets grown on nickel foam using the Successive Ionic Layer Adsorption Reaction (SILAR) method. The best-performing electrode shows a remarkable specific capacitance (Cs) of 2002 Fg-1 at 1 Ag-1 and Cs retention of 85 % for 10,000 GCD cycles. The assembled CB/NF-2//AC device exhibits high cycling stability and achieves a high energy of 52.2 Whkg-1 at a power density of 2622.4 Wkg-1. Remarkably, it reached 152.7 Fg-1 at 2 Ag-1, and the device still has a high capacitance retention of 85 % for 10,000 cycles. This remarkable electrochemical activity could be attributed to: (i) the inherent defects of the prepared electrode via the existence of borates, providing straightforward interaction between the electrolyte and the active species; (ii) designing the hierarchical architecture that could provide a porous nanosheet structure, which generates accessible active sites for quick ion transport, boosting the Cs; (iii) the formation of crystalline Cu-Bi nanosheets, resulting in high stability and superior electrochemical performance compared to the previous amorphous borides; and (iv) the hybridization between the B 2p state and the multiple d-orbitals of transition metals, increasing the electron flow between the atoms. The current work suggests that the growth of hierarchically crystalline Cu-Bi on Ni foam using a low-cost and simple procedure could provide a practical approach to designing hybrid supercapacitors with outstanding electrochemical performance.

Development of CuAlO2-Encapsulated Reduced Graphene Oxide Nanocomposites: An Efficient and Selective Electrocatalyst for Detection of Neurodegenerative Disorders

Carbon-based nanomaterials continue to simulate wide interest in diverse disciplines including electrochemical biosensors, which have great ability to function as next-generation clinical diagnostics. Motivated by this point, we for the first time developed a CuAlO₂-encapsulated reduced graphene oxide (rGO) nanocomposite by a facile wet-chemical process to modify a glassy carbon electrode for dopamine detection with high selectivity and good sensitivity. The size, shape, phase purity, chemical composition, and surface area were investigated for the samples through transmission electron microscopy, scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and Brunauer-Emmett-Teller analysis. The electrocatalytic performance was studied using cyclic voltammetry and amperometric technique. The modified rGO/CuAlO₂ nanocomposite electrode showed an enhanced electrochemical performance compared to other electrodes and pure CuAlO₂ electrodes due to the strong promoting effect between rGO and CuAlO₂. Both the oxidation current and concentration were proportional and show a linear range of 9.2 × 10^-8 to 1.6 × 10^-7 M having a detection limit of 15 nM at S/N = 3. Further, the biosensor successfully neglected the interference of ascorbic and uric acid and exhibited enhanced selectivity, improved sensitivity, and stability toward dopamine formulations. Most obviously, the real-time analysis of the electrochemical biosensor may be proved using the clinical diagnostics in the near future.